Samples taken on Sept. 9 showed levels of cylindrospermopsin, produced by certain types of cyanobacteria or blue-green algae, above EPA guidance values for recreational use.
The city says that people and pets should not ingest or swim in the water and signs will be posted at access points to the Barton Creek Greenbelt near Sculpture Falls.
This incident is different from previous incidents of harmful algae in the Austin area in several ways, according to the city. It is a different toxin with different health effects and was found in water samples rather than in the algae, which increases the risk of human exposure from recreational use. In addition, the toxin was found at a popular swimming hole in a creek environment, rather than in a lake or reservoir.
Harmful algae may also be present in other Central Texas creeks and lakes, along with microscopic organisms such as bacteria and parasites. The city advises people and pets to avoid warm, stagnant water and steer clear of any discolored or foul-smelling water.
People and pets should rinse off after being in a natural water body and avoid swimming for a few days after heavy rainfall when bacteria levels tend to be higher, says the city. There can also be physical dangers with uneven depths, debris, slippery surfaces, and strong currents.
Cylindrospermopsin may cause liver and kidney damage. According to the EPA, acute human and animal health effects of exposure to this toxin include:
- Bloody diarrhea
Anyone who thinks they have been exposed it advised to seek medical treatment immediately and call 311 to report possible illness in people or pets from harmful algae.
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